From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.2 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 87CB2C4727E for ; Thu, 1 Oct 2020 17:13:32 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 25FA420872 for ; Thu, 1 Oct 2020 17:13:32 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=mvista-com.20150623.gappssmtp.com header.i=@mvista-com.20150623.gappssmtp.com header.b="Bi5Rf+Iy" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732805AbgJARMx (ORCPT ); Thu, 1 Oct 2020 13:12:53 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54836 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732808AbgJARMU (ORCPT ); Thu, 1 Oct 2020 13:12:20 -0400 Received: from mail-ot1-x342.google.com (mail-ot1-x342.google.com [IPv6:2607:f8b0:4864:20::342]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id EFC2FC0613D0 for ; Thu, 1 Oct 2020 10:12:19 -0700 (PDT) Received: by mail-ot1-x342.google.com with SMTP id s66so6212362otb.2 for ; Thu, 01 Oct 2020 10:12:19 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=mvista-com.20150623.gappssmtp.com; s=20150623; h=date:from:to:cc:subject:message-id:reply-to:references:mime-version :content-disposition:in-reply-to:user-agent; bh=/7NXXrjXj8dvlBu8u10badCJ3wqHRyH8Ya1Qhmj1R7w=; b=Bi5Rf+IyCzanLkVYVcnuRBQTCJgAyhtqyqmmhN+PwflWucC/fDLF2BBMdJgYdhjFxU NfxshNeJPPU/Rx1rAEEc394ukeofq1lkaVjxNLsSQvVeuSfIKzg4V4ZKmkMrJwqB3DHC mekl9rpOfurpNlML/WeVFDTAVcrJ1+qHrj//+LTRFE/eaYc7PDxE9UDU0d2yXBrrNpbh 8NFvNB33XSSajw9EaRwHez/55svl0FY2e+0eaXShX0Hw3h76bnGo9bH1qSj4JrtXdLPj /9P+V/dDakIiiHxXiMtQTuGLbgYSSFam0x0jNRpLyjrUTvcxmY20lCelx63P9fxPmQGe gtlg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:reply-to :references:mime-version:content-disposition:in-reply-to:user-agent; bh=/7NXXrjXj8dvlBu8u10badCJ3wqHRyH8Ya1Qhmj1R7w=; b=AmKRhLxdpX2td2kVyuLMmBDCtNbwNgUeSG6aZZya29pvddIUQ9ESj7uu6L+UI3qGLJ h22ANt5FDXrccKUBZafXDT8WlpF4/TK2KM/VoEZDqjIJc0L4jxaHteFr7HyeuGBnxwX4 st7VsFRnVIaHT5v3BjVACckW0N69OakKAg8h6RGE0C5p2rdFwJN/8OlpJfCc5A3sZWwF jz9mZbZS26xYo8YcIoJnPtxTtLD9trwfW6E7TaaqN4ek49djWjMzHDmyFqoKEfi3sW9E /9HByesO0IeC2SAyiodcAzbjAmYLlEN18SLKX3IA8sEGkIJCl4TLRdCzX1Q1jkJ6OAVj uk/A== X-Gm-Message-State: AOAM532d0VJSGHghRCtPsdd8NpbqXNTGDK+UInLJ08ik3pNuKLbdYu3E YY2CmpYYQQslp4Tk8MAJF9ZmVA== X-Google-Smtp-Source: ABdhPJwtW9F8cfkV4bYuT1doxPf91zIYNcupz9lpvPbeAFuR507sRWYuX99lNIGCmvSyv6rAwcCXJw== X-Received: by 2002:a9d:61d5:: with SMTP id h21mr5820968otk.187.1601572339273; Thu, 01 Oct 2020 10:12:19 -0700 (PDT) Received: from minyard.net ([2001:470:b8f6:1b:119c:a18f:647:7f4c]) by smtp.gmail.com with ESMTPSA id p8sm1457125oot.29.2020.10.01.10.12.17 (version=TLS1_2 cipher=ECDHE-ECDSA-CHACHA20-POLY1305 bits=256/256); Thu, 01 Oct 2020 10:12:18 -0700 (PDT) Date: Thu, 1 Oct 2020 12:12:16 -0500 From: Corey Minyard To: "Luck, Tony" Cc: Borislav Petkov , Corey Minyard , Andy Lutomirski , "linux-edac@vger.kernel.org" , "hidehiro.kawai.ez@hitachi.com" , "linfeilong@huawei.com" , "liuzhiqiang26@huawei.com" Subject: Re: [PATCH v2] x86: Fix MCE error handing when kdump is enabled Message-ID: <20201001171216.GY3725@minyard.net> Reply-To: cminyard@mvista.com References: <20200929211644.31632-1-minyard@acm.org> <20200930175633.GM6810@zn.tnic> <20200930184906.GZ3674@minyard.net> <20201001113318.GC17683@zn.tnic> <20201001134449.GB3674@minyard.net> <20201001161645.GD17683@zn.tnic> <6c6238c0088747a994a2bdce38ad0242@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <6c6238c0088747a994a2bdce38ad0242@intel.com> User-Agent: Mutt/1.9.4 (2018-02-28) Precedence: bulk List-ID: X-Mailing-List: linux-edac@vger.kernel.org On Thu, Oct 01, 2020 at 04:29:49PM +0000, Luck, Tony wrote: > >> I was thinking about this some yesterday. It seems to me that enabling > >> IRQS in an MCE handler is just a bad idea, but it's really a bad idea > >> for kdump. > > > > I don't think this code ever thought about kdump. > > How useful is kdump after a machine check induced crash anyway? > > kdump is useful for debugging software problems. There are very > few ways that a software bug can result in a machine check. There > are many ways that a hardware problem can trigger a machine check > and crash. > > So it would seem (statistically) that the analysis of almost every kdump > after a machine check just says "h/w issue". I don't really know. It seems like having an idea of what the software was doing when the hardware died might be useful for the hardware engineers. I really don't know much about what triggers MCEs, though, besides memory errors the hardware couldn't correct. You could say that the regs don't matter, I suppose, and that's probabaly fine. But if it's easy enough to do, and the interfaces are already there and work, and it speeds up the crash process a bit, why not do it? -corey